The Duchy of Lancaster Act 1920 (c.51) The Duchy of Lancaster Act 1920 (c.51) Changes not yet applied. Later legislation changes this provision in ways not yet written into the text below: Sch. 2 para. 34 repealed by Horserace Betting and Olympic Lottery Act 2004 Sch. 6 6Paragraph 6 The Duchy of Lancaster Act 1920 (c.51)